If the answer above is None it means there is no specific mention in the legislation, but you still need to ask local law enforcement before drinking in Cameroon.
It is prohibited for any person with a liquor license to sell or supply alcohol beverages to anyone under 18 years of age. The law permits adults from the ages 18 to 21 to consume, purchase and buy alcohol beverages if accompanied by a person 21 years of age or older. Anyone over the age of 21 years may buy or consume alcohol unaccompanied.
You can find more legal details and links here:
Wikipedia Legal Drinking Page